Railway wheels consist of wheels used in vehicles that move on rails. Such vehicles are used, for example, for the transport of materials and people.
The most common vehicle to use this type of wheel is a railway train, which is interconnected to several cars classified according to what is being transported. When the train transports passengers, it is named passenger train; when transporting materials, it is named freight train.
Out of the aspects that are studied and analyzed in a railway system, the most important, and of interest, are: train derailment; maintenance costs; and efficient logistics strategies.
Train derailment it is generally caused due to loss of friction between the railway wheels and the rails, causing the train to lose contact with these elements.
This loss of friction causes the train to get off the rails, causing accidents and severe damages due to the large dimensions and high mass of the train.
Regarding maintenance costs, the railway wheels/the rails interaction it plays a vital role not only in maintaining trains but also in fuel consumption, safety, and ride quality for passenger trains. Finally, a derailment potentially affects the logistics contract, which may have financial implications due to loss of cargo or even loss of life resulting from rail accidents.
The main causes of train derailment are: wheels/rails interaction, broken rails, weld failures, rail geometry imperfections, rail gauge failure, and broken wheels.
All factors cited after “wheels/rails interaction” also resulting from this same phenomenon. In other words, broken rails, gauge failure, rail geometry, and weld failure may directly or indirectly affect the “wheels/rails interaction”. To name one example, a damaged railway wheels profile can cause rail geometry failures and surface imperfections, which in turn lead to excessive wheel wear.
Therefore, it is of great interest and importance to design and use a monitoring system and method for railway wheels that prevents accidents due to poor wheel condition or wheels/rails interaction failures.
In the state of the art, such monitoring is periodically performed, and the operation of the train and its cars must be stopped in order to verify the rail wheels.
Such verification is manually performed by one or more workers, who walk along the train checking its wheels and identifying which ones are excessively worn and need to be replaced.
However, this method requires a very long execution time and is subject to human failures, since the verification is manually performed by the workers. Furthermore, because verifications occur in a periodic basis, there is a great risk of a wheel suffering excessive wear or deformation over the period between verifications.
The state of the art also comprises some documents that disclose a monitoring of railway wheels, and they are described below.
A document comprising the state of the art is U.S. Pat. No. 8,925,873, which discloses a device and method for measuring and verifying dimensions related to wear of wheels on rails. This device consists of fast actuation cameras associated with laser meters, configured to construct a model of the wheel and thus verify dimensions such as angle of attack, wheel misalignment, and other dimensions that are related to premature wear of this element.
The application of the device and method of U.S. Pat. No. 8,925,873 allows verifying the premature wear of the wheels and decrease the number of necessary maintenances, avoiding accidents caused by the premature wear of these elements.
In U.S. Pat. No. 8,925,873 the device is installed on both sides of each rail to perform a partial modeling of the wheel or truck (combination of two wheels with an axle) of the equipment. The images captured by the camera and the laser sensors are obtained during the passage of the train, and it is not necessary to stop the train to perform measurement.
The images obtained by the cameras are then subjected to triangulation with the lasers to generate an accurate image of the wheel and read its dimensions.
However, said method allows only a measurement of the wheels by means of the images obtained by the device, not being possible to compare them with other wheels in perfect condition or with an ideal wheel model to determine the effective wear of the wheel.
The method described in the American document also does not allow to verify dimensions not captured by the cameras or sensors, such as the surface of wheels that is in contact with rails, making it impossible to check for anomalies in this section of the wheel and verify the wheel/rail interaction.
Moreover, the device does not allow using only cameras, requiring the application of laser sensors to perform the modeling of the wheel being monitored, thus increasing the cost of the device.
Another document of the state of the art is patent application US20140285658, which discloses a method and device for measuring wheels on rails without contact with the wheels. The device consists of cameras and laser sensors, installed near the rail or operated by an operator, configured to capture images of the wheel. The device can also be combined with a position sensor for greater accuracy when mounting each image.
The device of US20140285658 allows capturing the wheel in whole or only a section of interest. When a wheel is captured in whole, a three-dimensional model of the wheel is made by a computer system, configured to process the images obtained by the cameras and lasers.
In the computer system described in US20140285658, it is possible to perform several types of wheel measurement, thus allowing verification of the dimensions of most of its components. In addition, the system also comprises an option of comparing a first three-dimensional model with other models obtained by the same device to check for possible wheel anomalies and deformations.
However, such device and method do not allow measuring the surface of the rail wheel, only measuring the wheel profile, preventing the identification of deformations on the wheel surface, such as protrusions, surface irregularities, and other types of problems. Since it does not allow measuring the wheel surface, the method described also prevents the verification of the wheel/rail interaction, which can generate direct costs such as accidents and indirect costs such as excessive fuel consumption and passenger discomfort.
Furthermore, the method disclosed in US20140285658 only allows comparison of the wheel models measured by the device with other wheel models also obtained by the device, being not possible to introduce an ideal wheel model to measure the effective wear of the wheel.
Thus, it is concluded that both the periodic technique of monitoring rail wheels and the devices and systems disclosed in the state of the art are not able to effectively verify the wheel surface, thus preventing the verification of the wheel/rail interaction.
Further, none of the devices, systems, and methods in the state of the art are capable of measuring effective wear of the wheel surface and profile, comparing it with an ideal wheel model.